Lectin-Free Diets: What You Need to Know

By Stephen T. Sinatra, M.D., F.A.C.C., F.A.C.N., C.N.S., C.B.T.

Move over gluten. There’s another dietary “demon” looking to overtake your perch as the “ingredient-du-jour” that we should be avoiding. It’s called lectin, and going “lectin-free” seems to be the newest trend in dieting. Many believe a lectin-free lifestyle can reverse or cure diseases, and some celebrities have even jumped onboard, claiming their health improved dramatically since cutting out lectins.

So what’s the deal with lectins? Are lectins really bad for you? Well, my view on lectins is similar to how I feel about gluten. Some people may very well benefit from limiting lectins. For the vast majority, though, they are perfectly fine and don’t pose any significant problems. Let me explain what lectins are and why I believe they’re not necessarily as troublesome as some would have you believe…

What Are Lectins?

Lectins are a type of protein found in plants that bind to carbohydrates. Plant foods high in lectins include corn, milk, legumes (beans, lentils, and peas), nuts (peanuts and cashews), seeds, grains, nightshades (eggplant, peppers, potatoes, and tomatoes), squashes, and certain fruits (mainly their seeds).

There are countless types of lectins, and researchers are still trying to figure out what all of these various compounds are capable of.

There’s some research indicating lectins could have important health benefits. A few studies point to possible antimicrobial effects and anticancer activity. And in a more “everyday” capacity, lectins bind to carbohydrates during the digestive process, helping to reduce their effects on blood sugar. This is obviously a boon for those with diabetes.

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On the flip side though, the same binding characteristic of lectins is what some experts say can make them so harmful.

Lectins and Inflammation

Though scientists have known about lectins for a long time, they were introduced to the general public by California cardiologist Steven Gundry, MD. Dr. Gundry is an integrative cardiologist whose focus in his practice has been dietary and lifestyle changes to improve heart health. In his 2017 book, The Plant Paradox, he connects lectins with a wide range of health problems, including autoimmune conditions, heart disease, diabetes, and neurodegenerative issues.

It’s Dr. Gundry’s belief that the binding of lectins to carbs in the body can interrupt proper communication between cells, which can lead to inflammatory reactions. Also, because “clingy” lectins attach themselves to the intestinal wall, problems can arise in people whose guts aren’t in the best of health. The intestinal wall can become more permeable, allowing food particles and other toxins to seep into the bloodstream, triggering inflammation as the body fights off these foreign invaders. (This is commonly referred to as “leaky gut.”)

Indeed, some research links lectins to inflammation (the root cause of countless diseases, including those mentioned above) and other harmful processes. In one study, researchers stated that, when lectins bind to cells lining the digestive tract, harmful local and systemic reactions take place. For this reason, they classified lectins as “antinutrients” and toxins. They continued, “Locally, [lectins] can affect the turnover and loss of gut epithelial cells, damage the luminal membranes of the epithelium, interfere with nutrient digestion and absorption, stimulate shifts in the bacterial flora and modulate the immune state of the digestive tract. Systemically, they can disrupt lipid, carbohydrate and protein metabolism, promote enlargement and/or atrophy of key internal organs and tissues and alter the hormonal and immunological status.”

Sounds confusing, right? After all, the veggies, legumes, nuts and seeds that contain lectins have long been cited by nutrition experts as some of the healthiest foods we can eat.

Should You Eliminate Lectins?

Clearly, the research is conflicting. Should you forgo lectins, or is it OK to eat lectin-containing foods?

The short answer is that for a small subset of people, avoiding lectin-rich foods is a good idea.

In those with chronic digestion problems (such as an inflammatory bowel disease or irritable bowel syndrome) or certain autoimmune conditions (like rheumatoid arthritis), eliminating foods high in lectins could alleviate unpleasant digestive or systemic symptoms.

Some people may also have a lectin allergy or sensitivity. In these cases, the allergic reaction is usually pretty immediate and can be severe. Of course, these folks would want to avoid lectin as much as possible. Lectin sensitivities or allergies can be genetic, but a lot of them develop later in life in patients who have compromised gastrointestinal systems.

(If you’re curious if you have a sensitivity, you can try an elimination diet. Cut out foods high in lectins, then slowly reintroduce them, one at a time, and watch for symptoms.)

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But for the vast majority of people who are otherwise healthy, foods high in lectins are perfectly safe to eat. In fact, it’s my belief that eliminating all lectin-rich foods from your diet, if you really don’t need to, is a bad idea. It forces you to avoid a vast array of nutritious, fiber-rich, health-promoting plant foods—and in the long run, the lack of variety could negatively affect you and your well-being.

How to Remove Lectins in Food

Moreover, if you’re really concerned about lectins, you don’t necessarily have to cut out these foods forever. The simple process of cooking can actually deactivate lectin and its potentially harmful effects.

Soaking beans overnight in water and some baking soda, then draining them and thoroughly boiling or pressure cooking them, can eradicate nearly all lectins. In fact, pressure cooking vegetables and legumes is also an excellent way to decrease lectin content in those plant foods.

Likewise, sprouting grains, seeds, and beans releases enzymes that reduce lectins, and the process of fermentation can cut the lectins in dairy and vegetables.

Bottom line, for some people, a lectin-free diet makes sense. But for the majority, I don’t think it’s worthwhile. As I’ve mentioned many times in the past, the key to a good diet or eating plan is how sustainable it is…meaning, is it something you can follow for the rest of your life, and also thrive on? And does it provide you with all the vitamins, minerals, and nutrients to stay healthy? A lectin-free diet removes such a large number of beneficial, nutritious foods from your diet that I don’t think it’s sustainable long term.

Balance is the key to life, and it’s the best way to approach diet, too. This is why my “diet” recommendation always has been, and will continue to be, the PAMM diet.


© 2018 HeartMD Institute. All rights reserved.

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  1. Tim Barnden

    on October 31, 2018 at 11:22 am

    A very well written and interesting article but:
    “In those with chronic digestion problems… …eliminating foods high in lectins could /alleviate/ unpleasant digestive or systemic symptoms.”
    Suerely you mean exacerbate?

  2. Dave

    on January 2, 2019 at 5:57 pm

    Thanks for this article. Very helpful for people looking into lectin free diets. Definitely agree that for some people, avoiding lectins can be a good idea that makes them feel much better and that overall, not everyone should necessarily avoid lectins. For people with optimal digestion, they can probably eat high lectin foods and enjoy the other nutritious benefits!

  3. cis

    on February 2, 2019 at 8:31 am

    But what about the claim that lectins could cause heart disease?
    Having just had someone young and active in my family suffer a (NSTEMI) heart attack last week,
    someone who eats lentils 2x week and chickpeas 3 times a week, no fried foods or takeaways,
    and salads for lunch every day… I am now wondering if he may be may be harmed by lectins…

  4. Debbie

    on February 6, 2019 at 3:26 pm

    Interesting that Blood types A,B,AB and O have different responses to lectins in various foods. This is something that became better known to the general public with the publication of ‘Eat Right For Your Type’ by Peter D’Adamo. My curiosity about studies related to this in scientific literature led to dadamo.com and this study among others see: https://www.researchgate.net/publication/287278846_Effect_of_plant_lectins_on_human_blood_group_antigens_with_special_focus_on_plant_foods_and_juices In the history of humanity, it appears this is a large part of why we cook many of our foods but so far in trying to find a study showing lists of the foods including tomatoes/other nightshades and the temperatures at which the lectins are minimized to completely disintegrated is difficult to find so far. It seems to me that if one were able to know the level of non-blood type friendly lectin containing foods that one could reduce or eliminate their lectins by cooking, then a better idea than listing them as ‘avoid’ foods would be to list as ‘avoid’ unless a)cooked for the time needed to disintegrate the lectins and/or suggest a maximum quantity and frequency of consumption in a diet that has variety and balance.
    I was able to find a study showing temperature and time with corresponding reduction of lectins in soybeans as an example and trying to answer my own questions because according to dadamo.com, blood type A negative secretor (which I am) food lists show tomatoes and other nightshades as foods to avoid but since finding that cooking and pressure cooking are known to disintegrate the lectins and having normal health and longevity in my family I wonder if the reason for never having had digestive problems related to nightshades/tomatoes may have more to do with the fact that raw tomato consumption has pretty much been small, equivalent to a half cup chopped up in salads a couple of times a week when I feel like having salads and canned tomato sauces and pastes in meals I use them for (including the occasional Pizza and Lasagna!) by virtue of their being cooked under pressure means that all this time the lectins in them were in fact, deactivated! (unable to find any literature so far quantifying lectins in samples of canned tomato sauces and pastes either.) It seems to me too that variety of foods including seasonal consumption is important to overall nutrition allowing for the good in foods to override the toxic effects and an exploration of ethnic cookery through cookbooks shows variety and seasonality of traditional meals to be true.
    If anyone has any study links or comments I would appreciate it!
    Thanks in advance!

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